Long-term electrocardiographic studies of patients with Duchenne's muscular dystrophy

Sequential electrocardiographic changes in 31 patients with Duchenne's muscular dystrophy (DMD) during a long-term follow-up study (over 7 years) were investigated. The patients were classified into 2 groups according to sequential changes in amplitude of the R wave in lead V1 (RV1): group I, in which RV1 decreased with age, and group II, in which it showed no consistent change with age. Group I consisted of 14 patients who died earlier (19 +/- 1 years) than those in group II (22 +/- 3 years). The highest RV1 values were similar in the 2 groups, but high RV1 values appeared at an earlier age in group I (10 +/- 3 years) than in group II (16 +/- 4 years). The amplitude of the R wave in lead V5 (RV5) decreased with age in both groups, and then increased at the age of 21 to 24 years in group II. The R/S ratio and depth of the Q wave did not show a consistent change during the follow-up period in most DMD patients. These results indicate that sequential changes in RV1 and RV5 are useful indicators of the severity of heart injury in DMD.